motor system Flashcards
the precentral gyrus
primary motor cortex
what are the three main subcortical areas involve din motor control
basal ganglia, cerebellum, brainstem
what does the motor cortex do
plan and initiate movement
what do the basal ganglia and cerebellum do
coordinate and correct movement
what does the spinal chord do
conducts info to the muscles
sequence of events in picking up a coffee cup
- visual info locates cup
- motor cortex plans reach and command movement
- spinal chord carries cortex info to hand
- motor neurons carry message to muscles
- sensory receptors in hand alert when cup is grasped
- sensory cortex receives message
- basal ganglia judges force required and cerebellum corrects movement errors
- spinal chord carries sensory info to the brain
which cortex is in charge of goals
parietal cortex, takes info from senses and initiates movements
which cortex is in charge of planning
prefrontal, plans movement
which cortex is in charge of sequencing
premotor cortex, coordinates the whole body
which cortex executes
primary motor, produces simple movements (not whole body)
organization of the OG homonculus on the somatosensory and motor cortexes
head on lateral side of brain, then hand to arm to trunk to leg to feet at the longitudinal fissure
ethological movement
natural movements, innate behaviour movement patterns
examples of ethological movements
defensive positions, grasping, chewing, licking, reaching
can be generated by stimulation of areas in motor cortex, intensity according to duration of stimulation
what supports the idea of the homonculus being maintained by ethological movements
types of movements seem to be clustered in the same area, such as hand and arm being close and causing reaching and grasping movement
do you need sensory info to reach an object
yes, both where the goal is located and where your body is in relation to it
movement lexicon
behaviours built by set movement patterns
ethological behaviours
damage to a cortical area only impairs the corresponding body part or muscle, T/F
false, it impairs entire movements
why are there similar movement sequences all over the cortex
for compensatory behaviours from intact areas when there is damage
what does damage to the primary motor cortex do
muscle weakness and impaired individual movements
damage to the premotor cortex does what
impairs complex movements that involving multiple body parts
what is the role of the neocortex and the motor planning areas together
blend prelearned basic movements that are integrated and refined, coordinate multiple limbs at once each doing different basic movements
the direction of movement and force is encoded by what
motor neurons, each tuned to their own preferred direction
ventral stream
perception of objects, vision to perception
dorsal stream
process info to guide action, vision to action
mirror neurons
active when you are doing something or when watchgin soomeone else do something
some neurons are specific to size of a target or distance to a target, T/F
true
core mirror neurons are specific T/F
False, they are goal directed movements
where are mirror neurons found
in the ventral (bottom) premotor area, some found in parietal and temporal
substantia nigra does what in motor control
its the reward system, releases dopamine
hyperkinetic movement disorder
excess movement, resulting from damage to the caudate and putamen (in basal ganglia)
examples of hyperkinetic disorders
huntington, tourettes, dyskinesias (unwanted writhing or twitching)
hypokinetic movement disorders
loss of movement, resulting from loss of dopamine input from substantia nigra, difficulty making voluntary movements
example of hypokinetic disorder
Parkinson’s
basal ganglia’s role in motor control
modulation and force
cerebellum’s role in motor control
precision and control, timing movements, correction
how does the cerebellum correct movement
receives plan of movement from the cortex, and visual and sensory input from the result, then uses both in order to correct and sends it back to the cortex to try again
what is the purpose of the flocculus
balance and eye movements, horizontal lobe at base of cerebellum
midline areas of the cerebellum control what
the midline of the body, the face and trunk, ipsilaterally
lateral areas of the cerebellum control what
limb and digit movements, contralaterally
why do they test your balance to see if you are drunk
because the cerebellum is for balance and is extremely sensitive to alcohol
brainstem’s purpose in motor control
specify coarse movements of the entire body
cat arching it’ back or coarse hair, running or walking, full body movements
corticospinal tract
starts in cortex ends in spine, affects trunk, limbs, digits
which part of the corticospinal tract does what
lateral does limbs and digits contraterally, anterior does trunk ipsilaterally
corticobulbar tract
starts in cortex and ends in face (bulbous fucking head), affects facial movements
where do the cortico- tracts originate from
layer V of the cortex (layer IV is the sensory, V and VI are motor)
where do 95% of motor pathways decussate (contralteralize, cross over)
the pyramids, a bump on the ventral side of the brainstem
spinal motor neurons
provide output between nervous system and the muscles
spinal motor neurons are afferent or efferent
efferent
where do spinal motor neurons synapse onto
the neuromotor junction
where do corticospinal tracts synapse onto
inter and motor neurons
how are spinal motor neurons and interneurons arranged
in a homonculus, with lateral motor neurons control hands and digits, intermediate control limbs, medial control trunk
muscles that control limbs are arranged in
pairs
extensor muscles move
limb away from the trunk, triceps
flexor muscles move
limb towards the trunk, biceps
what is the neurotransmitter at the neuromuscular junction, controlling flexor or extensor
acetylcholine
can an extensor and flexor muscle both be excited at the same time
normally no, but through top down control yes, like engaging your core when doing another workout
